Edge bead removal apparatus

ABSTRACT

An edge bead removal apparatus is provided. The edge bead removal apparatus includes a clamping unit configured to clamp a cylindrical reticle and cause the cylindrical reticle to incline with a pre-determined angle and to rotate around a central axis. The edge bead removal apparatus also includes an edge bead removal solvent nozzle configured to spray an edge bead removal solvent to remove edge beads on both edges of the cylindrical reticle.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the priority of Chinese patent application No.201310222206.4, filed on Jun. 5, 2013, the entirety of which isincorporated herein by reference.

FIELD OF THE INVENTION

The present invention generally relates to the field of semiconductormanufacturing technology and, more particularly, relates to edge beadremoval apparatus and edge bead removal methods thereof.

BACKGROUND

A photolithography process, transferring patterns on a mask to asubstrate by an exposure process, is a important process of thesemiconductor manufacturing technology. The photolithography process isa core step in the manufacturing of large scale integrations (LSIs). Thecomplex and time-consuming photolithography processes of thesemiconductor manufacturing are mainly performed by correspondingexposure apparatus. Further, the development of the photolithographytechnology or the improvement of the exposure apparatus are mainlyfocused on three factors: feature size, overlay resolution, and yield.

In the manufacturing of a semiconductor device, the photolithographyprocess may include three main steps: changing wafers on the waferstages; aligning the wafers on the wafer stages; and transferringpatterns on the mask to the wafers. These three steps may besequentially repeated on the same wafer stage.

Since the photolithography process is a key step of the semiconductormanufacturing process, how to improve the yield of an exposure apparatusin the practical manufacturing process has become a very importanttopic. Various exposure apparatus with twin-stages have been developedin past a few years in order to further increase the yield of theexposure apparatuses. The exposure apparatus with twin-stages may referthat when one wafer stage is performing an exposure, the other waferstage may perform wafer alignment simultaneously, thus the wafer waitingtime may be reduced; and the exposure efficiency of the exposureapparatus may be improved.

Another more advanced exposure apparatus is a cylindrical reticlesystem. The cylindrical reticle system may include a base and a waferstage group for holding wafers on the base. The wafer stage group mayinclude a plurality of wafer stages moving between a first position anda second position in a circular manner. Further, the cylindrical reticlesystem may include an alignment detection unit configured above thefirst position of the base. The alignment detection unit may be utilizedto detect stage fiducials on the wafer stage at the first position andthe alignment marks on a wafer on the wafer stage at the first positionto align the wafer. Further, the cylindrical reticle system may alsoinclude a recticle stage on the second position of the base configuredto hold a cylindrical reticle, and cause the cylindrical reticle to ratearound a central axis of the reticle stage. The cylindrical reticle maybe a hollow cylinder, and may have an imaging area and non-imaging areasat both sides of the imaging area. Further, the cylindrical reticlesystem may also include an illuminator box locating in the hollowcylindrical reticle to irradiate light through imaging area. Further,the cylindrical reticle system may also include an optical projectionunit (lens) between the reticle stage and the base. The opticalprojection unit may be utilized to project the light passing through theimaging area of the cylindrical reticle onto an exposure region on thewafer on the wafer stage. When the wafer on the wafer stage moves fromthe first position to the second position and performs a unidirectionalscan along a scan direction, the cylindrical reticle stage may rotatearound the central axis for one cycle, the light passing through theimaging area of the cylindrical reticle may be projected onto the waferon one wafer stage; and a column of exposure regions of the wafer alongthe scanning direction may be exposed.

The imaging area of the cylindrical reticle may include transparentregions and opaque regions; and the transparent regions and the opaqueregions may form mask patterns. When an exposure light irradiates theimaging area of the cylindrical reticle, the light passing through thetransparent regions may be projected onto the photoresist layer on thewafer, thus patterns corresponding to the mask patterns on thecylindrical reticle may be formed in the photoresist layer on the wafer.

The opaque regions of the imaging area of the cylindrical retile areusually formed by forming an opaque material layer on the imaging area,followed by etching the opaque material layer. When the opaque materiallayer is etched, a photoresist layer may often be formed on the opaquematerial layer. The photoresist layer may also be formed on thenon-imaging areas of the cylindrical reticle. The photoresist layerformed on the non-imaging areas may contaminate the wafer stages of thecylindrical reticle apparatus. Thus, it may need a method to completelyremove the photoresist layer formed on the end edges of the cylindricalretile.

FIG. 1 illustrates a cylindrical reticle having a photoresist layer. Asshown in FIG. 1, the cylindrical reticle 104 includes a middle imagingarea 43 and two non-imaging areas 41 at both sides of the imaging area43. After forming a photoresist layer 109 on the cylindrical recticle104, the imaging area 43 of the cylindrical reticle 104 is covered bythe photoresist layer 109. The non-imaging areas 41 and side surfaces 31of the cylindrical reticle 104 are also partially or completely coveredby the photoresist layer 109. In order to form patterns on thecylindrical reticle 104, an exposure process is needed to expose thephotoresist layer 109 on the imaging area 43 of the cylindrical reticle104. Before performing the exposure process, the cylindrical reticle 104having the photoresist layer 109 has to be installed in the reticlestage of a photolithography apparatus. The photoresist layer 109 on bothend edges of the non-imaging areas 41 (may be referred as edge beads)and side surfaces 31 of the cylindrical reticle 104 may contaminate thereticle stage of the photolithography apparatus. Thus, the alignment ofthe cylindrical reticle 104 may be affected, and the particlecontaminations of the photolithography apparatus may be beyond thedesired requirements. The disclosed device structures, methods andsystems are directed to solve one or more problems set forth above andother problems.

BRIEF SUMMARY OF THE DISCLOSURE

One aspect of the present disclosure includes an edge bead removalapparatus. The edge bead removal apparatus includes a clamping unitconfigured to clamp a cylindrical reticle and to cause the cylindricalreticle to incline with a pre-determined angle and to rotate around acentral axis. The edge bead removal apparatus also includes an edge beadremoval solvent nozzle configured to spray an edge bead removal solventto remove edge beads on both edges of the cylindrical reticle.

Another aspect of the present disclosure includes a method for using anedge bead removal apparatus. The method includes providing a cylindricalreticle having a formed photoresist layer; and clamping the cylindricalreticle to incline downwardly with a pre-determined angle. The methodalso includes moving an edge bead removal solvent nozzle close to asurface of one end edge of the cylindrical reticle. Further, the methodalso includes spraying an edge bead removal solvent to the surface ofthe end edge of the cylindrical reticle to remove a portion of thephotoresist layer on the surface of the end edge of the cylindricalreticle.

Other aspects of the present disclosure can be understood by thoseskilled in the art in light of the description, the claims, and thedrawings of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a cylindrical reticle with a photoresist layer;

FIG. 2 illustrates an edge bead removal apparatus consistent with thedisclosed embodiments;

FIGS. 3-11 illustrate apparatus structures corresponding to an exemplaryedge bead removal process consistent with the disclosed embodiments; and

FIG. 12 illustrates an exemplary edge bead removal process consistentwith the disclosed embodiments.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary embodiments of theinvention, which are illustrated in the accompanying drawings. Whereverpossible, the same reference numbers will be used throughout thedrawings to refer to the same or like parts.

FIG. 2 illustrates an edge bead removal apparatus consistent with thedisclosed embodiments.

As shown in FIG. 2, the edge bead removal apparatus may include aclamping unit 103. The clamping unit 103 may be configured to clamp acylindrical reticle 104; and cause the cylindrical reticle 104 toincline and rotate around a center axis of the cylindrical reticle 104.

The cylindrical reticle 104 may be a hollow cylinder; and a surface ofthe cylindrical reticle 104 may have an imaging area 43 and twonon-imaging areas at both sides of the imaging area 43. The twonon-imaging areas may include a first non-imaging area 41 and a secondnon-imaging area 42. Mask patterns may be formed on the imaging area 43of the cylindrical reticle 104. The exposure light source of an exposureapparatus may irradiate the imaging area 43; and the mask patterns maybe transferred to a photoresist layer on a wafer. The first non-imagingarea 41 and the second non-imaging area 42 may be at two ends of theimaging area 43, respectively, thus it may be convenient for theclamping unit 103 to clamp the cylindrical reticle through thenon-imaging areas without mechanically damaging the imaging area 43 ofthe cylindrical reticle 104. Further, referring to FIG. 2, thecylindrical reticle 104 may also have a first side surface 44 and asecond side surface 45.

Referring to FIG. 2, the clamping unit 103may include a first suspendingarm 101 and a second suspending arm 102. A shaft (not labeled) may befixed at one end of the second suspending arm 102. Further, a firstbearing (not labeled) and a second bearing (not labeled) may beinstalled on the shaft. The first bearing may be installed at one end ofthe shaft near to the second suspending arm 102; and the second bearingmay be installed on one end of the shaft far from the second suspendingarm 102.

The first bearing and the second bearing may all include a bearing outerring (not shown), a bearing inner ring (not shown) and rolling elements(not shown) between the bearing inter ring and the bearing outer ring.The bearing inner ring of both the first bearing and the second bearingmay be fixed on the shaft. The cylindrical reticle 104 may be installedon the bearing outer ring of the first bearing and the bearing outerring of the second bearing by a robotic arm. The inner surface of thenon-imaging area 42 of the cylindrical reticle 104 may contact with thebearing outer ring of the first bearing and the bearing outer ring ofthe second bearing. After installing the cylindrical reticle 104 in arecticle stage, when the first bearing and the second bearing rotatearound the center axis of the reticle stage, the cylindrical reticle 104may also rotate around the center axis.

In one embodiment, the first suspending arm 101 may be a movable arm,before installing the cylindrical reticle 104, the first suspending arm101 may be detached from the shaft. After the cylindrical reticle 104 isinstalled on the first bearing and the second bearing, the firstsuspending arm 101 may move back to the shaft, and the first suspendingarm 101 may be fixed on the end of the shaft again.

In certain other embodiments, the first bearing and the second bearingmay be electromagnetic bearings. The electromagnetic bearing may includea bearing outer ring, a bearing inner ring and coils between the bearingouter ring and the bearing inner ring. The rotation of the bearing outerring may be precisely controlled by adjusting current distributions ofthe coils.

Further, the clamping unit 103 may also include a first driving unit 11.The first 11 driving unit may be configured to drive one end of thecylindrical reticle 104 to incline downwardly. The clamping unit 103 mayalso include a second driving unit 12. The second 12 driving unit may beconfigured to drive the cylindrical reticle 104 to rotate around thecenter axis. After a layer of photoresist is coated on the cylindricalreticle 104, the end of the cylindrical reticle 104 which needs an edgebead removal process may be inclined downwardly. When an edge bead on anend edge of the cylindrical reticle 104 is removed, edge-bead removalsolutions and edge-bead removal wastes may be unable to affect thephotoresist layer on the image area 43 of the cylindrical reticle 104.

Further, as shown in FIG. 2, the edge bead removal apparatus may alsoinclude an edge bead removal (EBR) solvent nozzle 105. The EBR solventnozzle 105 may be configured to spray an edge bead removal solvent tothe photoresist layer on the ends of the cylindrical reticle 104; andremove edge beads.

The EBR solvent nozzle 105 may connect with a third driving unit 13. Thethird driving unit 13 may drive the EBR solvent nozzle 105 to move closeto or far away from surfaces of both end edges of the cylindricalreticle 104. That is, when one end of the cylindrical reticle 104inclines downwardly to a pre-determined position, the third driving unit13 may drive the EBR solvent nozzle 105 to adjust a distance between theEBR solvent nozzle 105 and the end edge of the cylindrical reticle 104.Such a distance may be used to adjust an amount of the to-be-removedphotoresist layer at the end edges (edge beads) of the cylindricalreticle 104.

Further, as shown in FIG. 2, the edge bead removal apparatus may alsoinclude a back rinse nozzle 106. The back rinse nozzle 106 may beconfigured to remove the photoresist layer on the first side surface 44and the second side surface 45 of the cylindrical reticle 104. The backrinse nozzle 106 may be fixed at a certain position. The back rinsenozzle 106 may also be a movable component.

Further, as shown in FIG. 2, the edge bead removal apparatus may alsoinclude a first gas nozzle 107. The first gas nozzle 107 may beconfigured to spray an inert gas to remove a residue edge bead removalsolvent on the surfaces of both end edges of the cylindrical reticle104. After removing the photoresist layer on the end edge of the firstnon-imaging area 41 and/or the second non-imaging area 42 by sprayingthe edge bead removal solvent using the EBR solvent nozzle 105, theresidue edge bead removal solvent may be left on surfaces of both endsof the cylindrical reticle 104. The residue edge bead removal solventmay further etch (remove) the photoresist layer. The residue edge beadremoval solvent may also contaminate chambers of subsequent processes.Because the edge bead removal solvent may often have a significantlystrong volatility, when the inner gas sprayed by the first nozzle 107 isused to remove the residue edge bead removal solvent, a volatilizationof the residue edge bead removal solvent may be speeded up, and theresidue edge bead removal solvent may be removed with a significantlyhigh speed.

The first gas nozzle 107 may be fixed at a certain position. The firstgas nozzle 107 may also be a movable component.

Further, as shown in FIG. 2, the edge bead removal apparatus may alsoinclude a second gas nozzle 108. The second gas nozzle 108 may beconfigured to spray an inert gas to remove the residue edge bead removalsolvent on the first side surface 44 and the second side surface 45 ofthe cylindrical reticle 104.

The second gas nozzle 108 may be fixed at a certain position. The secondgas nozzle 108 may also be a movable component.

In one embodiment, the inert gas may be N₂. N₂ may have a significantlystrong chemical stability, thus it may be unable to etch the photoresistlayer. Further, N₂ may be relative cheap, thus the production cost maybe reduced. In certain other embodiments, other appropriate inert gasmay also be used.

FIG. 12 illustrates an exemplary edge bead removal process consistentwith the disclosed embodiments; and FIGS. 3-11 illustrate apparatusstructures corresponding to certain stages of the exemplary edge beadremoval process consistent with the disclosed embodiments.

As shown in FIG. 12, at the beginning of the edge bead removal process,a cylindrical reticle having certain structures is provided, andtransferred to an edge bead removal apparatus (S101). FIG. 3 illustratesa corresponding apparatus structure.

As shown in FIG. 3, a cylindrical reticle 104 with a photoresist layer109 is provided. The photoresist layer 109 may cover an entire firstimaging area 43. The photoresist layer 109 may also cover entire orpartial first non-imaging area 41 and the second non-imaging area 42. Aportion of the photoresist layer 109 at the end edge of the firstnon-imaging area 41 and a portion of the photoresist layer 109 at theend edge of the second non-imaging area 42 may be significantly thickerthan other portions of the photoresist layer 109, thus the portion ofthe photoresist layer 109 at the end edge of the first non-imaging area41 and the portion of the photoresist layer 109 at the end edge of thesecond non-imaging area 42 may be referred as edge beads. When thephotoresist layer 109 is formed on the cylindrical reticle 104, two sidesurfaces, a first side surface 44 and a second side surface 45, may alsohave some residue photoresist.

Various methods may be used to form the photoresist layer 109 on thecylindrical reticle 104. In one embodiment, the photoresist layer 109 isformed by an imprinting method. An apparatus of the imprinting methodmay include a base; a precision control stage moving reciprocally alonga scanning direction on the base; and an imprinting mask. The imprintingmask may have a plurality of trenches; and the trenches may be throughthe imprinting mask. The trenches may be used to hold a photoresist. Theapparatus may also include a photoresist nozzle above the imprintingmask. The photoresist nozzle may be used to spray photoresist on theimprinting mask. Further, the apparatus may include a reticle stageframe. The reticle stage frame may be used to hold a cylindricalreticle; and cause the cylindrical reticle to rotate around a centeraxis. The reticle stage frame may also be used to move the cylindricalreticle to cause a surface of the cylindrical reticle to contact with asurface of the imprinting mask.

When the trenches of the imprinting mask are full of photoresist sprayedby the photoresist nozzle, the surface of the cylindrical reticle 104may contact with the surface of the imprinting mask. Then, the precisioncontrol stage may move along the scanning direction, and the cylindricalreticle 104 may rotate around the center axis simultaneously. Thus, thephotoresist may be coated on the surface of the cylindrical reticle 104.

In certain other embodiments, other appropriate coating apparatus andmethods may also be used to form the photoresist layer 109 on thecylindrical reticle 104.

After forming the photoresist layer 109 on the cylindrical reticle 104,the cylindrical reticle 104 having the photoresis layer 109 may betransferred into the disclosed edge bead removal apparatus. A clampingunit of the edge-bead removal apparatus may clamp the cylindricalreticle 104 having the photoresist layer 109. Then, one side of thecylindrical reticle 104 may be inclined downwardly. In one embodiment,as shown in FIG. 3, the first side surface 44 of the cylindrical reticle104 is inclined downwardly.

Returning to FIG. 12, after proving the cylindrical reticle 104 with thephotoresist layer 109 and transferring the cylindrical reticle into theedge bead remove apparatus, the cylindrical reticle 104 may be movedclose to an edge bead removal (EBR) solvent nozzle; and inclined to apre-determined angle (S102). FIG. 4 illustrates a correspondingapparatus structure.

As shown in FIG. 5, the cylindrical reticle 104 with the photoresistlayer 109 is moved to an EBR solvent nozzle 105; and the first sidesurface 44 of the cylindrical reticle 104 with the photoresist layer 109is inclined downwardly with a pre-determined angle “α”. The angle “α”may refer to an angle between the center axis and a vertical direction.The vertical direction may be the direction of the gravity field. Whenthe cylindrical reticle 104 is titled to a pre-determined angle, thegravity force may be utilized to achieve an edge bead removal process.

In one embodiment, the angle “α” may be in a range of approximately45°˜90°. Further, the cylindrical reticle 104 may incline to the EBRsolvent nozzle 105, thus, as shown in FIG. 4, an angle “β” between thecylindrical reticle 104 and a spray direction of the spray nozzle 105may an acute angle. In one embodiment, the angle “β” between thecylindrical reticle 104 and the spray direction of the EBR solventnozzle 105 may be in a range of approximately 10°˜60°.

Referring to FIG. 4, when the EBR solvent nozzle 105 sprays an edge beadremoval solvent onto the photoresist layer 109 on the end edge of thefirst non-imaging area 41 of the cylindrical reticle 104, the sprayededge bead removal solvent may contact with the surface of thecylindrical reticle 104 along a downwardly inclining angle, thus anupward splashing and/or a back splashing of the edge-bead removalsolvent may be prevented. The upward splashing and/or the back splashingof the edge bead removal solvent to the photoresist layer 109 on theimaging area 43 of the cylindrical reticle 104 may affect a uniformityof the photoresist layer 109.

Further, as shown in FIG. 4, after moving the cylindrical reticle 204close to the EBR solvent nozzle 105 and inclining the cylindricalreticle 104 with a pre-determined angle, the EBR solvent nozzle 105 anda back rinse nozzle 106 may be moved to adjust a distance between thesurface of the first non-imaging area 41 of the cylindrical reticle 104and the EBR solvent nozzle 105 and a distance between the first sidesurface 44 of cylindrical reticle 104 and the back rinse nozzle 106 topre-determined values.

Returning to FIG. 12, after moving the cylindrical reticle 204 close tothe EBR solvent nozzle 105 and inclining the cylindrical reticle 204with a pre-determined angle, the photoresist layer 109 on the end edgeof the first non-imaging area 41 (edge bead) and the residue photoresistlayer 109 on the first side surface 44 may be removed (S103). FIG. 5illustrates a corresponding apparatus structure.

As shown in FIG. 5, the photoresist layer 109 on a surface 110 of theedge of the first non-imaging area 41 and the residue photoresist layer109 on the first side surface 44 are removed by spraying an edge beadremoval solvent. The edge bead removal solvent sprayed by the EBRsolvent nozzle 105 may be used to remove the photoresist layer 109 onthe edge of the first non-imaging area 41 (may be referred to an edgebead); a surface 110 of an end edge of the cylindrical reticle 104 maybe cleaned and exposed. The edge bead removal solvent sprayed by theback rinse spray nozzle 106 may be used to remove the photoresist layer109 formed on the first side surface 44 of the cylindrical reticle 104.When the photoresist layer 109 on the end edge of the first non-imagingarea 41 and the residue photoresist layer 109 on the first side surface44 are being removed, the cylindrical reticle 104 may rotate around thecenter axis; and a centrifugal force may be generated to the edge beads.The centrifugal force may aid the used edge-bead removal solvent toleave the surface of the first non-imaging area 41.

The edge bead removal solvent sprayed by the EBR solvent nozzle 105 andthe back rinse nozzle 206 may include any appropriate chemicals. In oneembodiment, the edge-bead removal solvent is organic solutions. The EBRsolvent nozzle 105 and the back rinse nozzle 106 may have significantlysmall apertures; and a flow of edge bead removal solvent may beprecisely controlled. A flow of the edge bead removal solvent of the EBRsolvent nozzle 105 may be in a range of approximately 1ml/min˜30ml/min.Such a flow may reduce a splashing and/or a scattering of the edge beadremoval solvent happening on the surface of the first non-imaging area41 when the edge bead removal solvent contacts with the surface of thefirst non-imaging area 41 with a moving angle. A flow of the edge-beadremoval solvent of the back rinse nozzle 106 may be in a range ofapproximately 1ml/min˜30ml/min.

A relative position (displacement) of the EBR solvent nozzle 105 may beused to control a width of the removed edge bead. The gravity force mayalso be used to control a distance of the removed edge bead from the endedge of the first non-imaging area 41.

When the EBR solvent nozzle 105 and the back rinse nozzle 106 arespraying the edge bead removal solvent, the cylindrical reticle 104 mayrotate around the center axis with a constant speed, thus a desiredmorphology of the photoresist layer 109 not being removed may beobtained. Further, the photoresist layer 109 on the end edge of thefirst non-imaging area 41 and the residue photoresist layer 109 on thefirst side surface 44 of the cylindrical reticle 104 may be completelyremoved, thus a contamination to chambers of subsequent processes causedby the photoresist layer 109 on the end edge of the first non-imagingarea 41 and the residue photoresist layer 109 on the first side surface44 of the cylindrical reticle 104 may be prevented.

In one embodiment, before the EBR solvent nozzle 105 and the back rinsenozzle 106 spray the edge bead removal solvent, the cylindrical reticle104 may have an accelerating rotation process, when the cylindricalreticle 104 reaches a constant speed, the EBR solvent nozzle 105 and theback rinse nozzle 106 may start to spray the edge bead removal solvent.After the photoresist layer 109 on the end edge of the first non-imagingarea 41 and the residue photoresist layer 109 on the first side surface44 of the cylindrical reticle 104 being completely removed, thecylindrical reticle 104 may have an deceleration process to stop.

Returning to FIG. 12, after removing the photoresist layer 109 on theedge of the first non-imaging area 41 and the residue photoresist layer109 on the first side surface 44 of the cylindrical reticle 104, residueedge bead removal solvent may be removed (S104). FIG. 6 illustrates acorresponding apparatus structure.

Referring to FIG. 6, the first gas nozzle 107 may blow an inner gas toremove the residue edge bead removal solvent on the end edge of thefirst non-imaging area 41. The second gas nozzle 108 may be used toremove the residue edge bead removal solvent on the first side surface44 on the cylindrical reticle 104.

Specifically, after removing the photoresist layer 109 on the end edgeof the first non-imaging area 41 and the residue photoresist layer 109on the first side surface 44 of the cylindrical reticle 104 by sprayingthe edge bead removal solvent, the EBR solvent nozzle 105 and the backrinse nozzle 206 may move away from the surface of the first non-imagingarea 41 and the first side surface 44. Then the first gas nozzle 107 andthe second gas nozzle 108 may move close to the surface of the firstnon-imaging area 41 and the first side surface 44. Alternatively, thecylindrical reticle 104 may move to cause the surface of the end edge ofthe first non-imaging area 41 close to the first gas nozzle 107; and thefirst side surface 44 close to the second gas nozzle 108. When adistance between the first gas nozzle 107 and the cylindrical reticle104 and a distance between the second gas nozzle 108 and the cylindricalreticle 104 reach a pre-determined value, the first gas nozzle 107 andthe second gas nozzle 108 may spray an inner gas to remove the residueedge bead removal solvent.

The inert gas may include any appropriate gas. In one embodiment, theinert gas is N₂.

Thus, a process for removing the photoresist layer 109 on the end edgeof the first non-imaging area 41 (edge bead) and the residue photoresistlayer 109 on the first side surface 44 of the cylindrical reticle 104may be completed. That is, the edge bead removal of the firstnon-imaging area 41 may be completed; and the surface 110 of thecylindrical reticle 104 near to the end edge may be completely cleaned.

After finishing the edge bead removal process of the first non-imagingarea 41 of the cylindrical reticle 104, the cylindrical reticle 104 maybe turned over, i.e., 180°. That is, as shown in FIG. 7, a second sidesurface 45 of the cylindrical retictle 104 is inclined downwardly.

Further, as shown in FIG. 8, the EBR solvent nozzle 105 and the backrinse nozzle 106 may move close to an end edge of the second non-imagingarea 42.

Further, as shown in FIG. 9, the EBR solvent nozzle 105 may spray theedge removal solvent to remove the photoresist layer 109 on a surface ofthe second non-imaging area 42 near to the end edge (may be referred toan edge bead); and the back rinse nozzle 106 may spray the edge beadremoval solvent to remove the photoresist layer 109 on the second sidesurface 45 of the cylindrical reticle 104. A surface 111 of thenon-imaging area 42 near to the end edge may be cleaned and exposed.

Further, as shown in FIG. 10, the first gas nozzle 107 may spray aninner gas to remove the residue edge bead removal solvent on the surfaceof the second non-imaging area 42 near to the end edge; and the secondgas nozzle 108 may spray the inert gas to remove the residue edge beadremoval solvent from the second side surface 45 of the cylindricalreticle 104.

Thus, an edge bead removal process of the second non-imaging area 42 onthe cylindrical reticle 104 may be completed.

After the edge bead removal process, the left photoresist layer 109 inthe imaging area 43, the first non-imaging area 41, and the secondnon-imaging area 42 may be exposed. Then, as shown in FIG. 11, thephotoresist layer in the first non-imaging area 41 and the secondnon-imaging area 43 may be completely removed after a developingprocess. Further, after the developing process, photoresist patterns maybe formed in the imaging area 43; and mask patterns may be subsequentlyformed on the imaging area 43 of the cylindrical reticle 104.

The above detailed descriptions only illustrate certain exemplaryembodiments of the present invention, and are not intended to limit thescope of the present invention. Those skilled in the art can understandthe specification as whole and technical features in the variousembodiments can be combined into other embodiments understandable tothose persons of ordinary skill in the art. Any equivalent ormodification thereof, without departing from the spirit and principle ofthe present invention, falls within the true scope of the presentinvention.

1. An edge bead removal apparatus, comprising: a clamping unitconfigured to clamp a cylindrical reticle and cause the cylindricalreticle to incline with a non-zero pre-determined angle and to rotatearound a central axis; and an edge bead removal solvent nozzleconfigured to spray an edge bead removal solvent to remove edge beads onboth edges of the cylindrical reticle.
 2. The edge bead removalapparatus according to claim 1, further including: a back rinse nozzleconfigured to spray the edge bead removal solvent to remove aphotoresist layer on both side surfaces of the cylindrical reticle. 3.The edge bead removal apparatus according to claim 1, further including:a first gas nozzle configured to remove residue edge bead removalsolvent on end edges of the cylindrical reticle by spraying an inertgas; and a second gas nozzle configured to remove residue edge beadremoval solvent on side surfaces of the cylindrical reticle by sprayingthe inert gas.
 4. The edge bead removal apparatus according to claim 3,wherein: the inert gas is N₂.
 5. The edge bead removal apparatusaccording to claim 1, wherein the clamping unit further includes: afirst suspending arm; and a second suspending arm.
 6. The edge beadremoval apparatus according to claim 1, wherein the clamping unitfurther includes: a first driving unit configured to incline one end ofthe cylindrical reticle downwardly with the non-zero pre-determinedangle.
 7. The edge bead removal apparatus according to claim 1, whereinthe clamping unit further includes: a second unit configured to drivethe cylindrical reticle to rotate around the center axis.
 8. The edgebead removal apparatus according to claim 1, wherein: a third drivingunit is connected with the edge bead removal solvent nozzle to drive theedge bead removal solvent nozzle to move close to or away from surfacesof both end edges of the cylindrical reticle.
 9. The edge bead removalapparatus according to claim 1, wherein: the cylindrical reticle is ahollow cylinder; and the cylindrical reticle has a middle imaging areaand two non-imaging areas at both sides of the imaging area.
 10. Theedge bead removal apparatus according to claim 5, wherein: a shaft isfixed at one end of the first suspending arm; and a first bearing andsecond bearing configured to install the cylindrical reticle are fixedon both ends of the shaft. 11.-20. (canceled)
 21. The edge bead removalapparatus according to claim 9, wherein: a photoresist layer is formedon a circumferential surface of the cylindrical reticle, two non-imagingareas at both sides of the imaging area includes a first non-imagingarea at a first end edge and a second non-imaging area at a second endedge, and the photoresist layer covers the first and second non-imagingareas.
 22. The edge bead removal apparatus according to claim 1,wherein: the clamping unit is configured to clamp and turn thecylindrical reticle for about 180°.
 23. The edge bead removal apparatusaccording to claim 1, wherein: the non-zero pre-determined angle is in arange of approximately 45°˜90°.